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Press Briefing Transcript

CDC Telebriefing on H7N9 Influenza Cases

OPERATOR: Thank you for standing by. During the question and answer session of today's call, you may ask a question by pressing star one. Today's conference is being recorded.

TOM SKINNER: Thank you, Shirley. Thank you all for joining us today for this telebriefing that we're having on an update of the situation around H7N9 infections in China. With us today is the director of the CDC, Dr. Tom Frieden who is going to provide some opening remarks and then we'll get to your questions where we'll be joined by Dr. Joe Bresee, a medical epidemiologist in our influenza division. With that, Dr. Frieden.

TOM FRIEDEN: Good afternoon, everyone. Thank you for joining us today. What we'll do is update you on the current situation with H7N9 in China. We're getting a lot of calls from the media, so we felt it would be most efficient for everyone to hold this telebriefing. We first want to update you about the situation in China and describe the steps that we at CDC are taking to protect health here in the U.S. We also want to put the outbreak in China into context and finally, of course, answer as many questions of yours that we can get to. I will provide an overview of the situation and of our response and I’d also like to just mention to you how CDC's relationship with the Chinese public health authorities is paying off in response to this outbreak for us and for people around the world and then I’ll be joined by the director of our influenza epidemiology unit, Dr. Bresee, who along with me will answer your questions.

As of April 5th, 2013, Chinese public health officials have reported 16 cases of human infection with a novel avian influenza A, which is called the H7N9 virus, from four different provinces in China. Patients were hospitalized and six of them have died. These are the first human infections with this particular strain of H7N9 that have been identified. 15 of the cases are among adults ages 27 to 87. The one child is age 4 and apparently had mild illness. All cases had onset between February 19th and March 31st, 2013. There has been no person-to-person transmission and no epidemiologic link between any of the cases so far. There are two families where there was illness in a family around the time of a confirmed case and those two family situations are being investigated by Chinese authorities to see if there was person-to-person transmission in those cases. I would say that with other avian influenza strains we sometimes see limited person-to-person transmission within the close contact of a family or health care but only one generation of spread or two generations of spread, not multiple generations of spread. So when we speak of person-to-person transmission, we really are looking at whether it's spreading widely.

Now, at this point, we are -- there are several things that give us some confidence that it's not spreading widely from person to person. One is that more than 100 contacts have been assessed and monitored by Chinese public health authorities and none of them have developed illness. In contrast, in influenza, you would expect at least 20 to 30 percent of family members to develop illness. So the fact that there are that many contacts and no illness has been identified is encouraging. In addition, many or perhaps most of the cases in the investigations are still ongoing have direct contact with live poultry. We also have reports from the Chinese Agricultural Authority that there are positive cultures for a similar strain of H7N9 from both chickens and pigeons and that further testing is under way. At this time, no cases of human infection with avian influenza A H7N9 have been detected in the United States.

CDC is working to address this situation as part of a coordinated international effort. First, today we issued a health advisory to inform clinicians and public health specialists throughout the U.S. of what is happening and what they should do if they have a suspected case in a traveler who is returning from China, what they should do in terms of testing, infection control, and care. We also have developed a test currently being used at CDC so that we can test specimens from travelers returning from China who have severe illness that might be this influenza and determine whether or not they have it. We will be taking further steps to develop a diagnostic test kit that we can send to states throughout the U.S. and to China so that we can have rapid diagnosis of infections going forward. The information coming out of China suggests that the virus is susceptible to two of the main antiviral agents we use, Oseltamivir and Zanamivir and we will be confirming that in the coming days, but that's what it looks like. Throughout the U.S. government and with pharmaceutical companies, the vaccine manufacturers out of an abundance of caution were developing a candidate virus that could be used to produce a vaccine if one is needed. This would only be produced if there were evidence of widespread transmission from person-to-person. That's not something that we are seeing at this time. We are not issuing any formal travel advisories. As I said earlier, a source for these infections has not been identified but we do know that the Chinese health authorities are starting to cull birds in live markets as a precautionary step and for about a decade we've already recommended to people in China to Americans traveling in China to avoid contact with birds and other animals. That's been in place since both SARS and the spread of another strain of influenza called H5 nearly a decade ago.

I want to take a moment to talk about CDC's relationship with the Chinese equivalent. The Chinese equivalent is called China CDC. And we have a very robust, long-term relationship with them. It got much stronger after SARS when China recognized that it needed to strengthen its public health system and we have an office that CDC maintains in China to collaborate. Over the course of many years our scientists have helped the Chinese public health doctors effectively monitor for influenza throughout the vast population of China, improve their laboratory testing for influenza, learn how to do genetic sequencing of the influenza strains that they identify, become a World Health Organization collaborating center for influenza and because of that, the Chinese government is able to track where influenza is spreading but we may not well have learned of these isolated cases and because of that, the Chinese government has posted publicly the full genetic sequence of the H7N9 strain that is affecting people in this cluster. In fact, I have a long -- a long-standing series of annual meetings and periodic updates with the director of the Chinese CDC and we had a long conversation late last night about this situation to ensure that we are providing any assistance that we can. We are working in concert against this to quickly identify the situation and take all appropriate steps.

Before I turn the call over to Dr. Bresee to answer your questions, I wanted to put this into perspective. Two questions that CDC is frequently asked are, how concerned are we and how concerned should the public be about the situation? And I’ll say this. We at CDC work 24/7 to protect people's health, including from threats such as emerging influenza viruses. We work to have the public's back. It's our job to be concerned and to move quickly whenever there's a potential problem, such as the one in China. And that's what we're doing. As far as should the public be concerned, there is no evidence at this point that the virus is being transmitted from one person to another or that the virus has caused any infections in the U.S.
There are no specific steps that people in this country need to take to protect themselves. People can go about their daily lives. Information can be a powerful anecdote for people who are worried or concerned. So what we're doing here is to communicate as much as we can of what we know when we know it completely openly. For many years, we have encouraged people in China, Americans in China not to have contact with live markets because influenza and other infections can spread and we continue with that recommendation. We will continue to provide updated information through our website as soon as we have it. We'll also continue as needed to update as there are developments. Thank you.

TOM SKINNER: Shirley, I believe we're ready for questions, please.

OPERATOR: Thank you. We will now begin the question and answer session. If you would like to ask a question, please press star 1. You will be prompted to record your name. Again, press star 1 to ask a question and one moment for our first question. Our first question comes from Elizabeth Weiss with USA Today go ahead with your question.

ELIZABETH WEISS: Thanks for taking my call. I wanted to ask a bit about the work on the seed strains for the virus. Can you talk a bit about when that was started and what -- where it stands currently?

TOM FRIEDEN: Because the genetic sequence is available, we're able -- and manufacturers are able to do reverse engineering [Editor’s note: “reverse engineering” is more accurately stated as “synthetic biology techniques”] to develop a potential vaccine strain. The Assistant Secretary for Preparedness and Response, Dr. Nicki Lurie and BARDA are in contract with pharmaceutical manufacturers who are also working in this area so that a seed strain can be available, if needed, as quickly as possible and the contracts that HHS, BARDA ASPR, as it's called, has with the manufacturers make sure that what they do is open source [Editor’s note: the candidate vaccine viruses developed as a result will be shared freely]. In other words, it would be available to anyone. I'd like to turn it over to Dr. Mike Shaw who is director of our influenza laboratory to address further issues.

MIKE SHAW: Right. Under this contract, the synthetic genes were created for BARDA and they are being shared. We are using them to try to develop a candidate vaccine strain as are companies. There are many different approaches to this. Many different companies and organizations are trying to work as quickly as possible to get the strain that would be shared as widely as possible to make sure that the vaccine production could receive it as quickly as possible.

TOM SKINNER: Do you have a follow up?

ELIZABETH WEISS: No that should do it.

OPERATOR: The next question comes from Miriam Falco, with CNN Medical News. You may ask your question.

MIRIAM FALCO: Hi, doctor. Thank you. I'm a little confused because according to the WHO press release, they say an additional five laboratory confirmed cases, including one death due to human infection with influenza A H7N9 virus and you've said twice now there hasn't been human-to-human transmission and one possible situation. I know you don't speak for the WHO but you guys obviously talk to them. Which one is it?

TOM FRIEDEN: So let's be clear. What we have is 16 reported, confirmed cases. All of those cases are isolated cases. There are no epidemiologic links that have been identified between the 16 different people. There are two of those 16 had other people ill in their families and that's continuing to be assessed to see if there was transmission within the family. And one thing to try to be clear about, we look at two things when we look at influenza. First, how virulent is the strain and second, how readily does it spread among people. In terms of that first question, how virulent or how deadly it is, we won't know until we are able to test a larger number of people and see if more than 16 people had it. It could be that hundreds of other people have mild infections and these people were the tip of the iceberg or it could be that it was a rare event that it passes from animals to people and that for those few people who are unfortunate enough to contract the infection from an animal, it's a very severe illness. The second question is, does it spread readily from one person to another? And everything we're seeing at this point suggests that at this point, that is not happening.

MIRIAM FALCO: So it's still accurate to say no human-to-human transmission?

TOM FRIEDEN: …has been documented, as of now. Correct.

MIRIAM FALCO: As of now. And then the other question I have is about this particular virus. It's the first time we've seen it in humans ever. Is there something about this virus that you think might make it more eligible to change quickly and quickly change to become more easily transmissible?

TOM FRIEDEN: One of the unusual characteristics of this virus is that in animals, it generally causes mild illness. So it's unusual, though not unheard of, for a virus to cause mild virus in animals but severe illness in people. And one possibility -- and we'll know this within the next week or so -- is that it's fairly widespread among animals. Sometimes when there are things like outbreaks of H5, you have a clue because there are bird die-offs or sick flocks. That may not be the case here. It's something we may find with time.

OPERATOR: Thank you. Our next question comes from Mike Stobbe with the Associated Press. You may ask your next question.

MIKE STOBBE: Thank you for taking my question. I apologize. I missed the first couple of minutes. Could you say a little more about the 16 cases, how old they were, what sex they were, and do they have any shared characteristics that might predispose them to more severe illness? And I had a follow-up question which was about, could you tell me about what the flu surveillance system is in China in is it a Marshfield Clinic type model or what is it that you have helped them develop there?

TOM FRIEDEN: Dr. Bresee will take the second part of that. Fifteen of the cases are in adults ages 27 to 87. One case is in a child, age 4. We do not have full information on predisposing medical conditions but it appears that many, if not most of the individuals, did have an epidemiologic link with live markets, with poultry. Dr. Bresee, on surveillance?

JOE BRESEE: The surveillance system in China has really dramatically improved over the last decade or so since the introduction of H5, the catalyst for that. They do a couple of things that is important. One is, they have a wide dispersion of labs that can detect flu, generally speaking, using the best methods, called PCR. They have well over 400 of these labs around the country that have grown up over that last few years. They really do have the ability to look for flu, wherever it is, in the country. They also have about an equal number of sites that looks for flu disease that tests people and count people, including both hospitalized people and people that come to clinics. If you think about China's ability to detect cluster of illness, to detect new illnesses, and to see how this potential outbreak may or may not spread, I think they are well positioned to do that.

TOM SKINNER: Mike, do you have a follow-up?

OPERATOR: One moment, please. Go ahead, Mike.

MIKE STOBBE: No. No. I don't have a follow-up.

TOM SKINNER: Next question, Shirley?

OPERATOR: The next question comes from Richard Knox with National Public Radio. You may ask your question.

RICHARD KNOX: Even though there isn’t any clear evidence of human-to-human transmission and I gather no signal of influenza-like increase in the area, Nancy Cox was telling me that genetic analysis indicates this virus might infect mammalian cells more easily than H5N1 does and I wonder how you can reconcile those two kinds of information and how heavily the genetic analysis of that weighs in your current threat assessment.

TOM FRIEDEN: So we always have to analyze the genetic sequence in concert with the epidemiologic pattern. It is true that some aspects of the genes of this organism are partially adapted to mammals, suggesting that they may have spent time in swine or other populations. But ultimately the fact that we haven't seen cases in contacts, that we haven't seen widespread cases in children, that we haven't seen a spike are all reassuring. And that most of the cases or many of the cases have had direct contact with the likely vector, I think all of that is reassuring. But, of course, one of the things that we look at very carefully is the continued evolution of influenza. Even if this organism ends up not going further than people who had a direct contact with animals, there's always the risk that it would continue to evolve in swine or other populations and become more transmissible in the future. And that's just to say we are at no larger risk today than we were two weeks ago before we all knew about it. But we always have to be prepared for emerging threats and that's why we monitor for them and that's why we respond very quickly when they may be emerging.

TOM SKINNER: Next question, Shirley?

OPERATOR: Next question comes from Richard Besser with ABC News. You may ask your question.

RICHARD BESSER: Thank you for taking my question. I have two. The first is, is there any way to tell how novel this virus is and whether there would be any population immunity? Have there been H7's or N9's that have circulated before? And the second is a follow-up to Richard Knox’s question. Is there any way to look at the virus to tell how many mutations would be needed to be spreadable from person-to-person?

TOM FRIEDEN: So because this virus has -- is not related to previously circulated influenza virus, there is not population immunity as far as we know to this particular strain of H7. Since it doesn't affect people, people haven't developed the immunity to it. And there is no specific way to say exactly what it would take to become better adapted to be able to spread person-to-person.

EBEN BROWN: Thank you very much. Appreciate the time, doctors. You had mentioned that there had been no cases in the United States reported. Are there any chances of this coming to somewhere else in the Western Hemisphere that could eventually then find its way into the United States?

TOM FRIEDEN: This is why we work with countries throughout the world to have a flu monitoring system and it's certainly possible that it could spread to countries neighboring China or to countries that have travelers to and from China who were in live markets. At this point, it looks like direct contact with live poultry in China is the main risk factor. But because flu can emerge anywhere in the world, it's in all of our best interests that there are good flu monitoring systems around the world and that's why when we do produce diagnostic kits, we distribute them to more than 100 countries and we help countries around the work to do their own flu surveillance. It protects them and it protects us.

MARYN MCKENNA: Thank you very much for this call. Can we hear a little bit more about what surveillance is like on the animal side in China? I think that Dr. Bresee was describing the human surveillance but I'd be interested in what is going on beyond the call of chicken in looking for this virus as it's moving through chickens or pigeons or whatever the suspected reservoir is.

JOE BRESEE: Thanks Maryn, this is Joe. I will say that the animal health authorities in China have issued guidance now for surveillance for this virus among poultry population, duck populations, and any bird populations that exist in markets in that area of China. They've engaged now in a very systematic surveillance system over the next week or so that intends to figure out what the scope of this virus is and what populations it might exist in. And so I think we can expect, as Dr. Frieden says, in the next week or two, some additional data to try to better to find the animal host of the virus which we think will be important in identifying prevention strategies for humans.

MARYN MCKENNA: Can I ask a follow-up to that?

JOE BRESEE: Sure.

MARYN MCKENNA: Can you -- is there anything else you can say about where that surveillance is taking place by which I mean, is it in people facing areas such as live markets, is it more out in the countryside? Are they looking at small farm holdings, the big new mega farms?

JOE BRESEE: That's a good question. What we're told by the Chinese authorities is that the extenuated surveillance will focus on those provinces that currently have human cases of the disease but be directed at both markets, industrial farms, and small holding farms.

MARYN MCKENNA: Super. Thank you.

TOM SKINNER: Next question?

OPERATOR: Thank you. Next question comes from Betsy McKay with the Wall Street Journal, you may ask your question.

BETSY MCKAY: Just a quick question about surveillance. I wondered what you all might know about what level of heightened surveillance there might be going on in other neighboring countries in Asia because of this.

JOE BRESEE: That's a good question. What we know now is that several of the countries in Asia, especially several of the bordering countries from China have been doing extenuated surveillance either in the community where they’re testing severely ill people to look for the introduction of this virus or occasionally in airports where they’re screening for fevers, for instance, of incoming passengers. I can't say that I know the exact scope of the extenuated surveillance going on, but we have heard from colleagues in Laos, Cambodia, Thiland, Taiwan and Vietnam that they’ve all heightened their surveillance in looking for this virus as have countries around the world, I might say.

BOB ROOS: Thank you. A couple of questions about the vaccine seed strain. I'm wondering if you have any existing vaccine seed strains for other H7 sub type viruses and if so if you plan to test those to see if they offer cross-protection and I wondered if this is the first time that you're trying to make a seed strain just from the DNA sequence without using an actual isolate?

TOM FRIEDEN: We do have strains of H7 but because this strain is so different, we don't expect that they would be protective. We have done reverse engineering to produce vaccine strains previously.

BOB ROOS: Thank you.

TOM SKINNER: Next question?

OPERATOR: Thank you. Next question comes from Jonathan Serrie with Fox News. You may ask your next question.

JONATHAN SERRIE: Good afternoon. If it becomes necessary to manufacture an H7N9 vaccine, how would its manufacture impact production of seasonal flu vaccine or would it become one in the same?

TOM FRIEDEN: If it became necessary and we should be clear that at this point that is not what appears to be happening, we do not think it would interfere with the ability to make seasonal vaccine. There are new technologies for vaccine production. We've been adding regularly BARDA has new manufacturers under way. We expect cell-based vaccine it to be available this year. We don't think it would affect availability of seasonal flu vaccine. [Editor’s note: At this time, we don’t think it would affect availability of seasonal flu vaccine.]

DONNA YOUNG: Thank you. I just was looking for a little bit of clarification again on this seed -- the seed virus that you're working on. Are the manufacturers working on that with you right now or is it strictly the government that's working on that and then you'll turn it over to the manufacturers?

TOM FRIEDEN: It's a joint project. The manufacturers are working – Novartis [working in collaboration with Synthetic Genomics Vaccines, Inc.], J. Craig Venter Institute, ourselves, manufacturers are on contract with BARDA, the U.S. government. We're doing it as a team in concert. Dr. Shaw, do you want to add anything to that?

MIKE SHAW: Right. It's a very wide effort right now looking at several different possibilities. There's the new recombinant vaccine that was recently approved that’s also an alternative. We’re not investing on a single pathway. There’s several different groups going at this.

TOM FRIEDEN: Thank you all for joining. Sunlight is the best disinfectant and there are concerns when we hear about people becoming severely ill and have died in China, the information we have so far suggests that all of the cases have been isolated, that they are mostly associated with spread of this virus in animals, likely poultry, chickens, ducks, geese, pigeons, perhaps. And we're in close collaboration with authorities in other countries, including China, so that we can rapidly learn more about where it's coming from and how -- whether it has spread from person-to-person. This is an example of why we need to keep our guard up and make sure we're prepared to detect and respond to threats as they emerge whether in this country or around the world. So thank you very much for joining.

TOM SKINNER: Thank you all for joining us. If you have the need for follow-up information, please call the CDC press office 404-639-3286. Thank you for joining us.
OPERATOR: Thank you. This does conclude today's conference. We thank you for today's participation. At this time you may disconnect your line.